textproduct: Quad Cities

KEY MESSAGES

- A blocked pattern will maintain a general northwest flow across the region for the first half of the period, with embedded waves and fronts combining with diurnal instability/heating to produce almost daily chances of precip in or near the forecast area.

- There is a Marginal (Level 1 out of 5) Risk for severe weather Monday afternoon for areas along and south of Highway 34. Primary threats are damaging winds and hail.

- Warm up for Sunday into Monday, before cooling back down into mid next week.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 154 PM CDT Sat May 2 2026

Enjoy a cool and dry afternoon before the next shortwave dives into the Northern Plains tonight. This trough will prompt a weak cold front to move in early Sunday morning from the northwest, advecting some mid-level moisture in from the Pacific and shifting winds out of the south. A short period of scattered (30-40%) rain showers is possible for the entire CWA between 3am and 10am with the frontal passage, and the lack of daytime heating should limit the instability and thunder potential with these showers. Current QPF forecasts have a trace to a few hundredths across the area. With clouds clearing and winds becoming westerly by Sunday afternoon, highs will climb into the low-to-mid 70s before plummeting overnight into the mid-40s with light and variable winds.

LONG TERM /MONDAY THROUGH SATURDAY/

Issued at 154 PM CDT Sat May 2 2026

Monday...Look for a rinse and repeat from Saturday night as another shortwave riding over a ridge in the Gulf of Alaska will cause the longwave trough over the Great Lakes to retrograde westward. A jet streak diving into Minnesota will support surface cyclogenesis across southwest Ontario Monday morning which forces another cold front southeastward across the northern Plains Monday afternoon. Again, our main moisture source will be in the mid-levels as southerly flow near the surface is currently forecasted to last for only 12-18 hours prior to frontal passage. Highs will be able to climb into upper 70s and low 80s though. With a stronger trough and daytime heating, MUCAPE values will be around 500 J/kg across the CWA ahead of the front, potentially above 1500 J/kg south of the I-80 corridor. This is why the SPC currently has a marginal (1 out of 5) risk for severe weather along and south of Highway 34 Monday afternoon into the evening where there is the greatest overlap in 0- 6 km effective bulk shear of 40 knots. Primary threats, currently, are damaging winds and hail as the unidirectional shear profile does not favor low-level helicity needed for tornadogenesis. The severe threat is forecasted to end overnight Monday as the front passes through, shifting the winds back to northerly.

Tuesday... Despite the cold air advection in the low-levels, a frontogenesis band between 700-500 mb will keep clouds around and the potential for a stratiform rain shield along and south of I-80. There is model uncertainty with the northern extent of this rain with the 25th percentile of the LREF having no QPF for the entire CWA while the 75th percentile has 0.1-0.2 inches of rainfall south of and along Highway 34. Regardless though, thunder probability on Tuesday remains less than 10%, and highs will be cool in the mid-to- upper 50s across much of the area. Things will dry out Tuesday night with partial clearing and lows slightly below average in the low 40s.

Wednesday-Thursday... The longwave trough over the Northern Plains finally ejects to the east Wednesday into Thursday as it picks up a trough in the subtropical jet over the Desert Southwest, setting up a 110+ knot jet streak from northern Texas up to Maine. While this jet streak will not be providing any dynamical support aloft over Iowa, a vorticity maximum over Wisconsin and some lingering mid-level moisture will provide the chance for some light showers Thursday afternoon into the evening before dry air is finally advected in Thursday night.

Friday-Saturday afternoon... Northwest flow aloft and a high pressure over the Great Lakes is expected to bring back the sunny skies and highs will rebound into the upper 60s and low 70s and light winds.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 625 PM CDT Sat May 2 2026

Sfc winds will back more to the southwest and south tonight and maintain 8-12 KTs ahead of an incoming frontal system that is currently off to the northwest of the region. With this front there will be an increase in mid clouds and a chance for some sctrd high based showers toward Sunday morning, but with the dry LLVLS it may be hard to precip-reduce VSBYs to MVFR levels. The pre-frontal south to southwesterly sfc winds will become gusty up over 20 KTs Sunday morning, then veer to the west as the afternoon progresses and the front slips through the area.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.